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From: "Darrick J. Wong" <darrick.wong@oracle.com>
To: Dave Chinner <david@fromorbit.com>
Cc: linux-xfs@vger.kernel.org
Subject: Re: [PATCH 25/30] xfs: scrub directory freespace
Date: Mon, 16 Oct 2017 15:37:08 -0700	[thread overview]
Message-ID: <20171016223708.GR4703@magnolia> (raw)
In-Reply-To: <20171016044921.GB3666@dastard>

On Mon, Oct 16, 2017 at 03:49:21PM +1100, Dave Chinner wrote:
> On Wed, Oct 11, 2017 at 06:43:26PM -0700, Darrick J. Wong wrote:
> > From: Darrick J. Wong <darrick.wong@oracle.com>
> > 
> > Check the free space information in a directory.
> 
> ....
> 
> > diff --git a/fs/xfs/scrub/dir.c b/fs/xfs/scrub/dir.c
> > index e2a8f90..a41310f 100644
> > --- a/fs/xfs/scrub/dir.c
> > +++ b/fs/xfs/scrub/dir.c
> > @@ -250,6 +250,426 @@ xfs_scrub_dir_rec(
> >  	return error;
> >  }
> >  
> > +/*
> > + * Is this unused entry either in the bestfree or smaller than all of them?
> > + * We assume the bestfrees are sorted longest to shortest, and that there
> > + * aren't any bogus entries.
> 
> s/We assume/We've already checked/

Ok.

> > + */
> > +static inline void
> > +xfs_scrub_directory_check_free_entry(
> > +	struct xfs_scrub_context	*sc,
> > +	xfs_dablk_t			lblk,
> > +	struct xfs_dir2_data_free	*bf,
> > +	struct xfs_dir2_data_unused	*dup)
> 
> ....
> 
> > +	while (ptr < endptr) {
> > +		dup = (struct xfs_dir2_data_unused *)ptr;
> > +		/* Skip real entries */
> > +		if (dup->freetag != cpu_to_be16(XFS_DIR2_DATA_FREE_TAG)) {
> > +			struct xfs_dir2_data_entry	*dep;
> > +
> > +			dep = (struct xfs_dir2_data_entry *)ptr;
> > +			newlen = d_ops->data_entsize(dep->namelen);
> > +			if (newlen <= 0) {
> > +				xfs_scrub_fblock_set_corrupt(sc, XFS_DATA_FORK,
> > +						lblk);
> > +				goto out_buf;
> > +			}
> > +			ptr += newlen;
> > +			if (endptr < ptr)
> > +				xfs_scrub_fblock_set_corrupt(sc, XFS_DATA_FORK,
> > +					      lblk);
> > +			continue;
> > +		}
> > +
> > +		/* Spot check this free entry */
> > +		tag = be16_to_cpu(*xfs_dir2_data_unused_tag_p(dup));
> > +		if (tag != ((char *)dup - (char *)bp->b_addr))
> > +			xfs_scrub_fblock_set_corrupt(sc, XFS_DATA_FORK, lblk);
> > +
> > +		/*
> > +		 * Either this entry is a bestfree or it's smaller than
> > +		 * any of the bestfrees.
> > +		 */
> > +		xfs_scrub_directory_check_free_entry(sc, lblk, bf, dup);
> > +
> > +		/* Move on. */
> > +		newlen = be16_to_cpu(dup->length);
> > +		if (newlen <= 0) {
> > +			xfs_scrub_fblock_set_corrupt(sc, XFS_DATA_FORK, lblk);
> > +			goto out_buf;
> > +		}
> > +		ptr += newlen;
> > +		if (endptr < ptr)
> > +			xfs_scrub_fblock_set_corrupt(sc, XFS_DATA_FORK, lblk);
> 
> I'd prefer this matches the loop logic order. ie.
> 
> 		if (ptr >= endptr)
> 

Ok.  That check can be lifted out of the loop anyway.

> > +		else
> > +			nr_frees++;
> > +	}
> > +
> > +	/* Did we see at least as many free slots as there are bestfrees? */
> > +	if (nr_frees < nr_bestfrees)
> > +		xfs_scrub_fblock_set_corrupt(sc, XFS_DATA_FORK, lblk);
> > +out_buf:
> > +	xfs_trans_brelse(sc->tp, bp);
> > +out:
> > +	return error;
> > +}
> > +
> > +/*
> > + * Does the free space length in the free space index block ($len) match
> > + * the longest length in the directory data block's bestfree array?
> > + * Assume that we've already checked that the data block's bestfree
> > + * array is in order.
> > + */
> > +static inline void
> > +xfs_scrub_directory_check_freesp(
> 
> No need for inline here, the compiler will do that automatically if
> appropriate.

Ok.  I'll make it STATIC like everything else here.

> > +	struct xfs_scrub_context	*sc,
> > +	xfs_dablk_t			lblk,
> > +	struct xfs_buf			*dbp,
> > +	unsigned int			len)
> > +{
> > +	struct xfs_dir2_data_free	*bf;
> > +	struct xfs_dir2_data_free	*dfp;
> > +	int				offset;
> > +
> > +	if (len == 0)
> > +		return;
> > +
> > +	bf = sc->ip->d_ops->data_bestfree_p(dbp->b_addr);
> > +	for (dfp = &bf[0]; dfp < &bf[XFS_DIR2_DATA_FD_COUNT]; dfp++) {
> > +		offset = be16_to_cpu(dfp->offset);
> > +		if (offset == 0)
> > +			break;
> > +		if (len == be16_to_cpu(dfp->length))
> > +			return;
> > +		/* Didn't find the best length in the bestfree data */
> > +		break;
> > +	}
> > +
> > +	xfs_scrub_fblock_set_corrupt(sc, XFS_DATA_FORK, lblk);
> > +}
> > +
> > +/* Check free space info in a directory leaf1 block. */
> > +STATIC int
> > +xfs_scrub_directory_leaf1_bestfree(
> > +	struct xfs_scrub_context	*sc,
> > +	struct xfs_da_args		*args,
> > +	xfs_dablk_t			lblk)
> > +{
> > +	struct xfs_dir2_leaf_tail	*ltp;
> > +	struct xfs_buf			*dbp;
> > +	struct xfs_buf			*bp;
> > +	struct xfs_mount		*mp = sc->mp;
> > +	__be16				*bestp;
> > +	__u16				best;
> > +	int				i;
> > +	int				error;
> > +
> > +	/*
> > +	 * Read the free space block.  The verifier will check for hash
> > +	 * value ordering problems and check the stale entry count.
> > +	 */
> > +	error = xfs_dir3_leaf_read(sc->tp, sc->ip, lblk, -1, &bp);
> > +	if (!xfs_scrub_fblock_process_error(sc, XFS_DATA_FORK, lblk, &error))
> > +		goto out;
> > +
> > +	/* Check all the entries. */
> > +	ltp = xfs_dir2_leaf_tail_p(mp->m_dir_geo, bp->b_addr);
> > +	bestp = xfs_dir2_leaf_bests_p(ltp);
> > +	for (i = 0; i < be32_to_cpu(ltp->bestcount); i++, bestp++) {
> > +		best = be16_to_cpu(*bestp);
> > +		if (best == NULLDATAOFF)
> > +			continue;
> 
> Count stale entries, check if matches hdr->stale ?

This should already be done by xfs_dir3_leaf_read ->
xfs_dir3_leaf1_read_verify -> __read_verify -> xfs_dir3_leaf_verify ->
xfs_dir3_leaf_check_int, right?

> 
> > +		error = xfs_dir3_data_read(sc->tp, sc->ip,
> > +				i * args->geo->fsbcount, -1, &dbp);
> > +		if (!xfs_scrub_fblock_process_error(sc, XFS_DATA_FORK, lblk,
> > +				&error))
> > +			continue;
> > +		xfs_scrub_directory_check_freesp(sc, lblk, dbp, best);
> > +		xfs_trans_brelse(sc->tp, dbp);
> > +	}
> > +out:
> > +	return error;
> > +}
> > +
> > +/* Check free space info in a directory freespace block. */
> > +STATIC int
> > +xfs_scrub_directory_free_bestfree(
> > +	struct xfs_scrub_context	*sc,
> > +	struct xfs_da_args		*args,
> > +	xfs_dablk_t			lblk)
> > +{
> > +	struct xfs_dir3_icfree_hdr	freehdr;
> > +	struct xfs_buf			*dbp;
> > +	struct xfs_buf			*bp;
> > +	__be16				*bestp;
> > +	__be16				best;
> > +	int				i;
> > +	int				error;
> > +
> > +	/* Read the free space block */
> > +	error = xfs_dir2_free_read(sc->tp, sc->ip, lblk, &bp);
> > +	if (!xfs_scrub_fblock_process_error(sc, XFS_DATA_FORK, lblk, &error))
> > +		goto out;
> > +
> > +	/* Check all the entries. */
> > +	sc->ip->d_ops->free_hdr_from_disk(&freehdr, bp->b_addr);
> > +	bestp = sc->ip->d_ops->free_bests_p(bp->b_addr);
> > +	for (i = 0; i < freehdr.nvalid; i++, bestp++) {
> > +		best = be16_to_cpu(*bestp);
> > +		if (best == NULLDATAOFF)
> > +			continue;
> 
> Count stale entries, check freehdr.nvalid + stale = freehdr.nused?

Aha, yes, that needs to be checked.

Also that for loop needs to be terminated on i < freehdr.nused.

--D

> Cheers,
> 
> Dave.
> -- 
> Dave Chinner
> david@fromorbit.com
> --
> To unsubscribe from this list: send the line "unsubscribe linux-xfs" in
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  reply	other threads:[~2017-10-16 22:37 UTC|newest]

Thread overview: 99+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-10-12  1:40 [PATCH v12 00/30] xfs: online scrub support Darrick J. Wong
2017-10-12  1:40 ` [PATCH 01/30] xfs: return a distinct error code value for IGET_INCORE cache misses Darrick J. Wong
2017-10-12  5:25   ` Dave Chinner
2017-10-12  1:40 ` [PATCH 02/30] xfs: create block pointer check functions Darrick J. Wong
2017-10-12  5:28   ` Dave Chinner
2017-10-12  5:48     ` Dave Chinner
2017-10-16 19:46       ` Darrick J. Wong
2017-10-12  1:41 ` [PATCH 03/30] xfs: refactor btree pointer checks Darrick J. Wong
2017-10-12  5:51   ` Dave Chinner
2017-10-12  1:41 ` [PATCH 04/30] xfs: refactor btree block header checking functions Darrick J. Wong
2017-10-13  1:01   ` Dave Chinner
2017-10-13 21:15     ` Darrick J. Wong
2017-10-16 19:48   ` [PATCH v2 " Darrick J. Wong
2017-10-16 23:36     ` Dave Chinner
2017-10-12  1:41 ` [PATCH 05/30] xfs: create inode pointer verifiers Darrick J. Wong
2017-10-12 20:23   ` Darrick J. Wong
2017-10-13  5:22     ` Dave Chinner
2017-10-13 16:16       ` Darrick J. Wong
2017-10-16 19:49   ` [PATCH v2 " Darrick J. Wong
2017-10-16 23:53     ` Dave Chinner
2017-10-12  1:41 ` [PATCH 06/30] xfs: create an ioctl to scrub AG metadata Darrick J. Wong
2017-10-16  0:08   ` Dave Chinner
2017-10-12  1:41 ` [PATCH 07/30] xfs: dispatch metadata scrub subcommands Darrick J. Wong
2017-10-16  0:26   ` Dave Chinner
2017-10-12  1:41 ` [PATCH 08/30] xfs: probe the scrub ioctl Darrick J. Wong
2017-10-16  0:39   ` Dave Chinner
2017-10-16 19:54     ` Darrick J. Wong
2017-10-16 23:05       ` Dave Chinner
2017-10-12  1:41 ` [PATCH 09/30] xfs: create helpers to record and deal with scrub problems Darrick J. Wong
2017-10-16  0:40   ` Dave Chinner
2017-10-12  1:41 ` [PATCH 10/30] xfs: create helpers to scrub a metadata btree Darrick J. Wong
2017-10-16  0:56   ` Dave Chinner
2017-10-12  1:41 ` [PATCH 11/30] xfs: scrub the shape of " Darrick J. Wong
2017-10-16  1:29   ` Dave Chinner
2017-10-16 20:09     ` Darrick J. Wong
2017-10-12  1:42 ` [PATCH 12/30] xfs: scrub btree keys and records Darrick J. Wong
2017-10-16  1:31   ` Dave Chinner
2017-10-12  1:42 ` [PATCH 13/30] xfs: create helpers to scan an allocation group Darrick J. Wong
2017-10-16  1:32   ` Dave Chinner
2017-10-12  1:42 ` [PATCH 14/30] xfs: scrub the secondary superblocks Darrick J. Wong
2017-10-16  5:16   ` Dave Chinner
2017-10-20 23:34     ` Darrick J. Wong
2017-10-12  1:42 ` [PATCH 15/30] xfs: scrub AGF and AGFL Darrick J. Wong
2017-10-16  2:18   ` Dave Chinner
2017-10-12  1:42 ` [PATCH 16/30] xfs: scrub the AGI Darrick J. Wong
2017-10-16  2:19   ` Dave Chinner
2017-10-12  1:42 ` [PATCH 17/30] xfs: scrub free space btrees Darrick J. Wong
2017-10-16  2:25   ` Dave Chinner
2017-10-16 20:36     ` Darrick J. Wong
2017-10-12  1:42 ` [PATCH 18/30] xfs: scrub inode btrees Darrick J. Wong
2017-10-16  2:55   ` Dave Chinner
2017-10-16 22:16     ` Darrick J. Wong
2017-10-17  0:11   ` [PATCH v2 " Darrick J. Wong
2017-10-17 21:59     ` Dave Chinner
2017-10-12  1:42 ` [PATCH 19/30] xfs: scrub rmap btrees Darrick J. Wong
2017-10-16  3:01   ` Dave Chinner
2017-10-12  1:42 ` [PATCH 20/30] xfs: scrub refcount btrees Darrick J. Wong
2017-10-16  3:02   ` Dave Chinner
2017-10-12  1:43 ` [PATCH 21/30] xfs: scrub inodes Darrick J. Wong
2017-10-12 22:32   ` Darrick J. Wong
2017-10-16  3:16     ` Dave Chinner
2017-10-16 22:08       ` Darrick J. Wong
2017-10-17  0:13   ` [PATCH v2 " Darrick J. Wong
2017-10-17 22:01     ` Dave Chinner
2017-10-12  1:43 ` [PATCH 22/30] xfs: scrub inode block mappings Darrick J. Wong
2017-10-16  3:26   ` Dave Chinner
2017-10-16 20:43     ` Darrick J. Wong
2017-10-12  1:43 ` [PATCH 23/30] xfs: scrub directory/attribute btrees Darrick J. Wong
2017-10-16  4:13   ` Dave Chinner
2017-10-12  1:43 ` [PATCH 24/30] xfs: scrub directory metadata Darrick J. Wong
2017-10-16  4:29   ` Dave Chinner
2017-10-16 20:46     ` Darrick J. Wong
2017-10-17  0:14   ` [PATCH v2 " Darrick J. Wong
2017-10-17 22:06     ` Dave Chinner
2017-10-12  1:43 ` [PATCH 25/30] xfs: scrub directory freespace Darrick J. Wong
2017-10-16  4:49   ` Dave Chinner
2017-10-16 22:37     ` Darrick J. Wong [this message]
2017-10-16 23:11       ` Darrick J. Wong
2017-10-16 23:14       ` Dave Chinner
2017-10-16 23:38         ` Darrick J. Wong
2017-10-17  1:10   ` [PATCH v2 " Darrick J. Wong
2017-10-17 22:08     ` Dave Chinner
2017-10-17 23:51       ` Darrick J. Wong
2017-10-12  1:43 ` [PATCH 26/30] xfs: scrub extended attributes Darrick J. Wong
2017-10-16  4:50   ` Dave Chinner
2017-10-12  1:43 ` [PATCH 27/30] xfs: scrub symbolic links Darrick J. Wong
2017-10-16  4:52   ` Dave Chinner
2017-10-12  1:43 ` [PATCH 28/30] xfs: scrub directory parent pointers Darrick J. Wong
2017-10-16  5:09   ` Dave Chinner
2017-10-16 21:46     ` Darrick J. Wong
2017-10-16 23:30       ` Dave Chinner
2017-10-16 23:58         ` Darrick J. Wong
2017-10-17  0:16   ` [PATCH v2 " Darrick J. Wong
2017-10-17 22:11     ` Dave Chinner
2017-10-12  1:43 ` [PATCH 29/30] xfs: scrub realtime bitmap/summary Darrick J. Wong
2017-10-16  5:11   ` Dave Chinner
2017-10-12  1:44 ` [PATCH 30/30] xfs: scrub quota information Darrick J. Wong
2017-10-16  5:12   ` Dave Chinner
2017-10-17  1:11     ` Darrick J. Wong

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